Compressed-gas circuit interrupter



Sept. 5, 1961 B. P. BAKER ETAL 2,999,143

COMPRESSED-GAS CIRCUIT INTERRUPTER Filed Nov. 21, 1956 5 Sheets-Sheet l Fig.l.

KNVENTORS WITNESSES Benjamin E Baker, Jack E. Schromeck and Richard E. Kane ATTORNEY Sept. 5, 1961 B. P. BAKER ET AL COMPRESSED-GAS CIRCUIT INTERRUPTEIR 5 Sheets$heet 2 Filed Nov. 21, 1956 Fig.2.

Sept. 5, 1961 B. P. BAKER ET AL COMPRESSED-GAS CIRCUIT INTERRUPTER 5 Sheets-Sheet 5 Filed Nov. 21, 1956 5 T I 1 k a a W 0S0 M\\ Ill b; 2%? x s s s s s s W mm Nm\ 8 a l [E mm mm WV a ,8 W/////N///////////////V////////WV/fi w Sept. 5, 1961 B. P. BAKER ETAL 2,999,143

COMPRESSED-GAS CIRCUIT INTERRUPTER Filed Nov. 21, 1956 5 SheetsSheet 4 Fig.4.

fi I F5? 7177 V85 Opening 12 Open 22 Position Posmon High Pressure High Pressure Close Sept. 5, 1961 Filed Nov. 21, 1956 B. P. BAKER ETAL COMPRESSED-GAS CIRCUIT INTERRUPTER 5 Sheets-Sheet 5 United States Patent 2,999,143 COMPRESSED-GAS CIRCUIT INTERRUPTE-R Benjamin P. Baker, Monroeville, Jack E. Schrameck,

Pittsburgh, and Richard E. Kane, Monroeville, Pa., as-

signors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Nov. 21, 1956, Ser. No. 623,567 26 Claims. (Cl. 200-148) This invention relates to circuit interrupters in general, and more particularly, to high-voltage circuit interrupters of the compressed-gas type.

A general object of the invention is to provide an improved compressed-gas circuit interru ter, which will be more effective in operation than those used hitherto.

A more specific object of the present invention is to provide an improved compressed-gas circuit interrupter particularly adapted for high-voltage application, and in which the several parts'are so constructed as to result in a strong and rigid assemblage.

Another object of the invention is to provide an improved compressed-gas circuit interrupter in which the isolating contacts are operated in a medium constantly maintained at high pressure.

Still, a further object of the invention is to provide an improved compressed-gas circuit interrupter incorporating a plurality of interrupting assemblies, in which the interrupting assemblies are electrically interconnected, and the structures thereof made more rigid, by the use of one or more movable isolating contacts, which form a bridging arrangement between the two interrupting assemblies.

Still, a further object of the present invention is to provide an improved interrupting assembly in which an auxiliary reservoir of high-pressure gas is maintained at high potential, and insulated from the grounded supporting structure by a current transformer compartment, the latter preferably containing an insulating gas of relatively high dielectric strength.

Yet, a further object of the present invention is to provide an improved operating arrangement for a compressed-gas circuit interrupter of simplified construction and highly reliable.

An additional object of the invention is toprovide an improved mounting arrangement fora compressed-gas circuit interrupter in which the space between the exterior weatherproof casing and the internal supporting cylinder is maintained as a gas pressure above that of atmospheric pressure, so that there will be no possibility of air containing moisture seeping through the supporting connections to lower the dielectric strength along the casing structure to result in the possibility of flashover.

Yet, a further object of the invention is to provide an improved potential device for a compressed-gas circuit interrupter, which is highly effective, yet which does not take up any space required for the operating mechanism or any of its associated operating parts.

United States Patents 2,627,005, issued January 27,

1953 to Benjamin- P. Baker, Erling Frisch, Wayne S. Aspey and John B. MacNeill; 2,616,008, issued October 28, 1952 to Benjamin P. Baker and Erling Frisch and 2,646,483, issued July 21, 1953 to Benjamin P. Baker and Howard M. Wilcox, all of the foregoing patents being assigned to the assignee of the instant patent application, describe an improved 69 kv. compressed-air circuit interrupter having an interrupting rating of 3,500,000 kva. This interrupter was particularly developed for indoor service. It is a further object of the present invention to improve the interruptingv structure set out in the foregoing patents to particularly adapt it for much higher ratings,

say 138 kv. at 10,000,000 kva. interrupting capacity, with a continuous current-carrying capacity of 2,000 amperes,

2,999,143 Patented Sept. 5, 1961 and to adapt such a modified structure for outdoor application.

It is an ancillary object of the present invention to adapt the compressed-gas circuit interrupter of the preceding paragraph for outdoor application in such a manner that the entire structure is very strong and rigid, being capable of withstanding earthquake shocks and other disturbances, with the several parts thereof, which may be relatively fragile, so supported and interbraced that the interrupter is particularly strong and highly effectively supported.

Further objects and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

FIG. 1 is a side elevational view of one pole of the three-phase compressed-gas circuit interrupter of the invention;

FIG. 2 is an end elevational view of the three poles of the three-phase circuit interrupter embodying the invention;

FIG. 3 is an enlarged, longitudinal vertical sectional view through one of the two isolating structures, the isolating contacts being illustrated in the closed-circuit position;

FIG. 4 is a diagrammatic view of one half of one of the poles of the circuit interrupter of FIGS. 1-3, illustrating the improved operating mechanism therefor, and the several contact structures being illustrated in the closed-circuit position;

FIG. 5 is a fragmentary, diagrammatic view of a portion of the operating mechanism in the opening position;

FIG. 6 is an enlarged, fragmentary, cross-sectional view taken substantially along the line Vl-VI of FIG. 4;

FIG. 7 is a side elevational view of the potential device of the interrupter illustrating the series capacitors, and with the external porcelain casing broken away; and

FIG. 8 is a vertical sectional view through the isolating structure taken substantially along the line VIII-VIII of FIG. 3.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral 1 generally designates an interrupting assembly supported by metallic side plates 2 to the outer sides of a longitudinally extending high pressure reservoir 3. As observed in FIG. 1, there are two such interrupting assemblies 1 supported upon the high-pressure tank 3, and they are interconnected, and interbr'aced, at their upper ends 4 by a pair of serially related isolating structures, generally designated by the reference numeral 5.

Generally, each of the interrupting assemblies, includes an auxiliary high-pressure reservoir 6, which is utilized to raise the pressure within a chamber '7, housing a pair of separable main contacts 8, 9 (FIG. 4), which are shunted by an impedance assemblage 134. The impedance assemblage 134 provides a laterally positioned impedance unit, such as a resistor 135 (FIG. 4) suitably encased in a weatherproof porcelain casing 10.

To interrupt the residual current passing through the resistor 135 of the impedance assemblage 134 during the opening operation, a pair of serially related separable contacts 11, 12 (FIG. 4) are provided. The movable contacts 8, 11 are movable within an operating cylinder 13 supported by one or more ribs 14 from an intermediate 3 being a side elevational view taken lengthwise along the middle pole B.

The general method of operation of the circuit interrupter pole B is as follows: First, a supply of compressed gas is admitted by suitable means to the chambers 7 and 18, which are normally at atmospheric pressure. This blast of compressed air is sufficient to cause upward, separating, opening motion of the movable main contact 8 upwardly within the operating cylinder 13, in opposition to the action exerted by a closing compression spring 19. This will cause the current through the interrupter to flow through the impedance assemblage 134 including the resistor 135 (FIG. 4), which may include a plurality of superimposed zig-zag grid castings, such as of the type illustrated in US. Patent 2,632,078, issued March 17, 1953 to Benjamin P. Baker and Erling Frisch, and assigned to the assignee of the instant application.

The forcing of the current through the interrupter through the resistor section 134 will obviously reduce the current flow therethrough and also improve the power factor. Subsequent to the transfer of the current through the resistor 134, the gas blast will be effective to cause downward opening separating motion of the movable impedance contact 11 downwardly within the operating cylinder 13, away from its cooperating stationary impedance contact 12. Gas will flow through the opening 20, through suitable cooling screens 21 composed of wire mesh, or the like, and exhaust out vent openings 22 provided in the upper end cover casting 4 of the interrupting assembly 1. In a similar manner, the, gas blast between the main contacts 8, 9 will flow through another opening 23 provided in the stationary main contact 9 and downwardly to exhaust laterally out of the auxiliary reservoir housing 6 through a side vent passage 24.

Following the separation of the impedance contacts 11, 12 and the interruption of the residual current therebetween, it will be obvious that this will interrupt the current flow through the interrupting assembly 1.' However, since the contacts 8 and 11 are spring-biased closed by the compression springs 19, 25, there are provided means to maintain the circuit open. For this purpose, there are a pair of cooperating isolating contacts 26, 27, which areenclosed within an isolating chamber 28, constantly maintained at high pressure, by an interiorly disposed insulating tension tube 29 and an exterior Weather proof casing 30, composed of a suitable weatherproof material, such as porcelain.

In fact, there are provided two pairs of isolating contacts 26, 2.7, as noted in FIG. 1, whose tension tubes 29 and whose weatherproof porcelain casings 30 provide a desirable interbracing between the interrupting assemblies 1. The porcelain casings 30 are secured together through an intermediately disposed hollow metallic casting 31, shown more clearly in FIGS. 3 and 4 of the drawings.

The circuit is maintained open through the interrupter following reclosure of the movable main contact 8 and the movable impedance contact 11 by maintaining the separation between the isolating contacts 26, 27 by the exhausting of pressure back to the movable, hollow, isolating contact 27.

An important feature of the present invention is the mounting of the auxilitary reservoir 6 at line, or high potential by means of an external weatherproof casing 32, preferably made ofa suitable weatherproof material, such as porcelain, and an interiorly disposed insulating tension tube 33, more clearly shown in FIGS. 4, 6 and 7 of the drawings. The space 34 (FIG. 4) within the tension tube 33 is employed to house a current transformer, generally designated by the reference numeral 35. Also, this space 34 is utilized to retain the transformer insulating fluid, which may be oil, air at elevated pressure, or

some other gas, such as sulfur hexafluoride SF This space 34.thus constitutes a current-transformer compartment for the circuit interrupter.

The space 36, within the porcelain casing 32 and exteriorly of the tension tube 33, as shown in FIGS. 6 and '4 7, may advantageously be utilized to support a plurality of serially related capacitor elements 37, which collectively may be used to form a potential device 38. A potential tap at 39 (FIG. 7) may be made by a lead connection 40 to measure the potential of the auxiliary reservoir 6 at high potential. The capacitor elements may be of the type illustrated in US. patent application filed December 20, 1954, S.N. 476,108, issued June 24, 1958', as United States Patent 2,840,670 to Robert E. Friedrich, Winthrop M. Leeds and Benjamin P. Baker, and assigned to the assignee of the instant application. The space 36, within which the capacitor elements 37 are positioned, is preferably maintained at a pressure of substantially 5 p.s.i. with clean, dry or another suitable gas. This prevents any leakage of atmospheric air within the interrupter, which if permitted to occur, might introduce the possibility. of breakdown over insulating surfaces because of accumulated moisture. FIG. 3 illustrates in considerable detail the structure associated with the isolating contacts 26, 27. With particular reference to this figure, it will be noted that the relatively stationary isolating contact 26 includes a plurality of split resilient stationary fingers, integrally formed with an end closure plate 41. The closure plate 41 is provided with a plurality of annular recesses 42, 43 which accommodate resilient gaskets 44, 45, the latter respectively abutting the weatherproof casing 30 and the interiorly disposed tension tube 29. As shown, the insulating tension tube 29 has an annular recess 46 provided at each end thereof, within which is disposed an annular metallic ring 47, each ring being engaged by a hook-shaped flange member 48. Each flange member 48 has a plurality of circumferentially spaced, tapped openings 49 therein to accommodate bolts 50, the latter passing through openings 51 in the closure plate 41 and in a casting section 52. The casting section 52, together with its cooperating half 53, collectively form the intermediate casting housing 31, previously referred to.

As a result of the foregoing construction, the bolts 50 will place the insulating tension tube 29 under tension, and the exteriorly positioned porcelain casing 30 under compression, the several gaskets 44, 45 maintaining hermetic seals. The region 54 (FIG. 3) between the tension tube 29 and the porcelain casing 30 is preferably maintained at 5 p.s.i. for the same reasons as set out hereinbefore, whereas the interior isolating chamber 28 adjacent the separable isolating contacts 26, 27 is main-' tained at high pressure, as provided by the auxiliary reservoir 6.

As noted in FIG. 3, the movable tubular isolating contact 27has a plurality of springs 55, 56 acting therein to bias the movable contact 27 against a stop 57, so

that good contacting engagement is made between the resilient fingers 26 and the outer end of the movable isolating contact 27, as illustrated in FIG. 3. In addition, the movable isolating contact 27 acts as a piston, movable within an operating cylinder 58, the region 59 within said operating cylinder 58 being exhausted at certain times, as set out hereinafter. A piston ring 60 is provideclto insure a gas-tight seal. An exhaust tube 61 extends through the region 54 between porcelain casing 30 and the insulating tube 29 and communicates by means. of a passage 62 with the regions 59 back of both movable isolating contacts 27. e

The operating mechanism 64 for. each interrupting assembly 1, will now be described. With particular reference to FIGS. 4 and 5 of the drawings, it will be noted that a blast valve 65, constituting a first valve means, closes an opening leading into the interrupting chambers 7, 18. The blast valve 65 operates within an upstanding operating cylinder 67, being biased upwardly towards its closed position, as viewed in FIG. 4.

by a closing compression spring 68. The region 69 back S to a valve stem 71, the upper end of which has a spring plate 72 secured thereto. The spring plate 72 is biased downwardly by a compression spring 73 so that the valve 70 is biased over a vent opening 74 leading to a vent passage 75. The valve 70 is movable within a chamber 76, which may be at a high pressure or at a low pressure, such as atmospheric pressure, depending upon the position of the valve 70. The valve stem 71 has its lower end forming a push rod, which may be engaged by a valve lever 77 pivotally mounted at 78 upon an upstanding bracket support 79. The valve lever 77 has an insulating operating rod 80 pivotally connected to its left-hand end at 81, as viewed in FIG. 4. The insulating operating rod 80 passes downwardly through the space 34 within the tension tube 33 to a piston cylinder 82. The lower end of the operating rod 80 is connected to an operating piston 83, slidable interiorly within the piston cylinder 82, and maintained in one of three different positions, namely, a closed position, as illustrated in full lines in FIG. 4, an intermediate open position, as indicated in dotted lines, or in the lowermost opening position, also indicated in dotted lines in FIG. 4.

The right-hand end of the valve lever 77 has a lost motion connection 84 with the valve stem 85 of a valve 86 constituting a part of a second valve means 140, the upper end of which is pivotally connected as at 87 to a rocking valve lever 88, pivotally mounted at a stationary fulcrum 89 on a bracket support 90. bracket support 90 is afiixed to the casing 91, enclosing an isolating control chamber 92, which may be at high pressure or at a lower pressure, such as atmospheric pressure, depending upon the position of the valve 86 and of another valve 93 also constituting a part of said second valve means 140, whose valve stem 94 is pivotally secured to the right-hand end of the rocking lever 88, as at 95. The casing 91 has a port 96 controlled by the valve 93, which opens directly into the high-pressure region 97 of the auxiliary reservoir 6. The valve 860 controls an opening 98, which opens into a vent passage 99, leading to the region exteriorly of the auxiliary reservoir 6. In addition, the isolating chamber 92 communicates with an exhaust tube 100, passing upwardly within insulating tension tubes 101, 102, disposed interiorly of the porcelain casings 16, 17 and communicating within the upper casting 4 with the horizontally extending exhaust tube 61 to the regions 59 in back of the movable isolating contacts 27.

The position of the operating piston 83 is controlled by an electropneumatic trip valve 103, having a two-way valve 104 operated by the armature 105 of a solenoid 106. The actuation of the two-way valve 104 may either permit high-pressure gas to flow from a high-pressure tube 107 to the upper end of the operating cylinder 82, or in the other position of the two-way valve 104, as shown in FIG. 4, may exhaust the upper end of the operating cylinder 82 through a pipe connection 108 and through a vent tube 109. As shown, the solenoid 106 is directly electrically connected by leads 110, 111 to the secondary 112 of the current transformer 35, so that the electropneumatic trip valve 103 will be operated upon the passage of excess, or fault, current through the interrupter B.

To effect the closing of the interrupter by a closing of the isolating contacts 27, there is provided a two-way electropneumatic closing-valve 113- connected to the armature 114 of a solenoid 115. The operation of the twoway valve 113 will either permit high-pressure gas to flow from a high-pressure conduit 116 and through a pipe connection 117 to the lower end of the operating cylinder 82, or in the other position of the two-way closing valve 113, thelower end of the operating cylinder 82 may be exhausted through a vent pipe 118 connected to the lower end of the valve casing 119 of the electropneumatic closing valve 113. The high-pressure reservoir 3, as viewed in FIG. 4, has a connection, as at 120, to a highpressure conduit 121, which communicates with the high- The pressure pipes 107, 116. The high pressure conduit 121 also communicates at its upper end with the region 97 interiorly of the auxiliary reservoir 6. As a result, the reservoir 6 is maintained at the same pressure as the lower disposed high-pressure tank 3, which is at ground potential. A pressure-reducing valve 122, disposed interiorly of the auxiliary reservoir 6, insures that the region 123 and the region 54 within the isolating structure 5 will be maintained at the aforesaid value of 5 p.s.i., these regions being pneumatically inerconnected by a connecting pipe 124. Also, a high-pressure pipe 125, passing through the chambers 7, 18, maintains the isolating chamber 28 at the same pressure as the auxiliary reservoir 6. In addition, a second reducing valve 126 may be employed to mainain the region 36 exteriorly of the tension tube 33 at 5 p.s.i.

The lost-motion connection 84, previously referred to, may include a laterally jutting portion 127 of the valve stem 85, the operation of which will be explained hereinafter. A lead connection 128 from the conducting auxiliary reservoir 6 may constitute the primary winding of the current transformer 35, with the lead 128 passing through an insulating bushing 129 and connected by a lead 130 through a second bushing 131 to terminate in a line terminal connection 132 of the pole unit B. The porcelain casings 16, 17 and the insulating tension tubes 101, 102, diagrammatically illustrated in FIG. 4, may have the same construction as was shown in FIG. 3 for the porcelain casing 30 and the interiorly disposed tension tube 29 of the isolating structure 5.

From the foregoing description, it will be apparent that the circuit through the pole unit B in the closed-circuit position of the interrupter, as shown in FIG. 4, is as follows: The current passes through the terminal connection 132 through the lead 130, through the bushing 129 and by way of the lead 128 constituting the primary winding of the current transformer 35. The current then passes by way of the conducting casing 6, constituting the high-pressure reservoir, to the upstanding conducting stationary contact support 9, through the movable main contact 8, and through the operating cylinder 13 t0 the movable impedance contact 11. The circuit then extends through the stationary impedance contact 12 and through the upper closure casting 4 to the resilient stationary isolating fingers 26. The circuit then extends through the movable isolating contact 27, and through the operating cylinder 58 to the intermediate casting housing 31. The circuit then extends through the right-hand isolating structure 5, and through the right-hand interrupting assembly 1 (FIG. 1) in a similar manner to that here inbefore described to the right-hand terminal connection 132.

When it is desired to open the electric circuit through the interrupter, suitable means operated by thestation attendant may be employed to momentarily effect the energization of the solenoid 106 of the electropneumatic trip valve 103. Or, as shown in FIG. 4, the passage of excess current, such as a fault current through the interrupter, will be reflected in a surge of secondary current in the current transformer 35, and this will be effective to energize the solenoid 106. In either event, the energizntion of the solenoid 106 will raise the armature to cause high-pressure gas from the high-pressure pipe 107 to pass through the pipe 108 to the upper end of the operating cylinder 82, to force the operating piston 83 downwardly to the lower extremity of the operating cylinder 82 to the opening position, as illustrated in dotted lines in FIG. 4. This action will rotate the valve lever' 77 in a counterclockwise direction about its stationary pivot 78 to the maximum extent, as indicated by the full lines of FIG. 5, thereby striking the push rod portion 71 of the valve 70, raising the same against the spring pressure of spring 73, closing port 133 and opening port 74. At the same time, the right-hand free end of the valve lever 77, as viewed in FIG. 5, will take up the '7 lost-motion connection 84 and strike the lower end of the valve stem 85, reversing the positions of valves 86, 93, as shown in FIG. 4, so that exhaust port 98 will be opened and port 96 will be closed. This condition is shown in FIG. 5.

The closing of the port 133 and the opening of vent port 74 by valve 70 will exhaust the region 69 below the blast valve 65, and since the high pressure within region 97 acts downwardly on the upper slanting surfaces of blast valve 65, the same will snap downwardly to permit high-pressure gas to pass through the opening 66 and upwardly into the interrupting chambers 7, 18 to elfect the sequential opening of the two pairs of contacts 8, 9 and 11, 1 2. As previously indicated, the opening of contacts 8, 9 will force the circuit to pass through the impedance section 134 reducing the value of the current andimproving the power factor, thereby enabling the circuit to be more easily interrupted; and the subsequent opening of the impedance contacts 11, 12 will interrupt the residual current, thereby halting all current flow through the interrupter.

The closing of the port 96 by the ball valve 92, as shown in FIG. 5, and the opening of the exhaust port 98.by the valve 86 will bring the region 92 within the casing 91 to atmospheric pressure by virtue of the vent passage 99; and this reduction in pressure will be transmitted upwardly through the exhaust tubes 61 and 100 to the regions 59 in back of both movable isolating contacts 27. Because of the time delay aflorded by the dumping of high-pressure gas downwardly through the exhaust tube 100,.the impedance contacts 11, 12 will have interrupted the residual current prior to the initial separation of the isolating contacts 26, 27. Thus, by the timethat the contacts 26, 27 in the isolating structure Shave opened in the high-pressure region 28 thereabout, the circuit will have been completely interrupted by the previous separation of the contacts 11, 12 and the interruption of the residual current thereacross.

Since the energization of the solenoid 106, as brought about by the current transformer 35, will be merely momentary, the compression spring 73 will be effective to cause reclosure of the valve 70 over the vent opening 74 to bring about a raising of the pressure within the region 76 and a consequent reclosure of the blast valve 65 over the blast opening 66 due to spring action 68. However, the high pressure within the region 97 will be efiective to maintain the ball valve 93 over the port 96 so that valve lever 77 will be forced to its intermediate open position, as shown by the dotted lines of. FIG. 5, and will stay in this position without the necessity.

of any solenoids being energized. This is so inasmuch as the weight of the right-hand'end of the valve lever 77.

will besutficient to maintain the operating piston 83 in the open? position. The weight of the armature 105 will effect reclosure of the valve 104, closing 011 the high-pressure pipe 107 and exhausting the upper end of the operating cylinder 82. Similarly, the closing solenoid 1 15 is normally deenergized, thereby causing atmospheric pressure to normally be at the lower end of the operating cylinder 82. As a result in the open-circuit,

position of the interrupter, the regions 59 in back of both movable isolating contacts 27 will be exhausted because of the low pressure codition existing within the casing 91, which condition will be maintained because of the closure of valve 93 over opening 96, as maintained by the high pressure within region 97 of auxiliary reservoir 6.

From the foregoing description, it will be apparent that the interrupter may be maintained open by the separation of the isolating contacts 26, 27 within the high-pressure region 28, thereby permitting only a small isolating distance because of the high dielectric strength of the high-pressure gas within region 28, while at the same'time the several solenoids associated with the interrupter may be deenergized, the weight of the righthand end of valve lever 77 being suflicient to maintain the piston 83 in the intermediate "open position, as shown by the dotted lines in FIG. 5. a r 1 When it is desired to close the electrical circuit through the interrupter, it is merely necessary to momentarily energize the closing solenoid 115 to efiect a raising of the armature 114 of the electro-pneumatic closing valve 113. This will permit high-pressure gas to feed through the high-pressure pipe 116, through valve casing 119 and through conduit 117 to the lower end of operating cylinder 82. This will force the operating piston 83 upwardly to its upper closed position, thereby rocking the valve lever 77 in a clockwise 'direction about its stationary pivot 78, causing the right-hand free end thereof to engage. the laterly jutting portion 127 of valve stem 85 and forcing the ball valve 93 upwardly away from the port 96 and simultaneously elfecting a closure of the ball valve 86 over the exhaust port 98. ,The casing 91 will rapidly fill with high-pressure gas from the region 97, and this high-pressure gas within the re gion 92 of the casing 91 will be effective to maintain the ball valve '86 closed over the vent opening 98, thereby permitting a deenergization of the closing solenoid 115. In other words, the closing solenoid 115 need merely be momentarily energized to reverse the positions of the ball valves 86, 93, and when this'is done, the pressure conditions within the casing 91 will maintain the ball valves 86, 93 in their reversed positions, thereby permitting a deenergization of the closing solenoid 115.

As be obvious from an inspection of FIG. 4,"the

raising of the pressure within the region 92 of casing 91 will result in a transmittal of this high-pressure upwardly through the exhaust tube and the horizontally extending exhaust tube 61 to elfect a raising of the pressure within the regions 59 back of both movable isolating contacts 27. The presence of the biasing springs 55, 56 will thereby effect a closure of the contacts 26, 27, and since this closure ofthe isolating contacts will take place in a high-pressure region 28, the contacts 26, 27 will be very close together before there is any possibility of prestriking thereacross during such a closing operation, this resulting because of the high-dielectric strength of the high-pressure gas within isolating chamber 28.

From the foregoing description, it will be apparent that the present invention considerably extends the cur-.

rent interrupting ability of the interrupter described in U.S. Patent 2,627,005 and renders the same suitable for the interruption of circuits up to 138 kv., and 10,000,000 kva. interrupting capacity, with 2,000 amperes continuous current and with the rating going even beyond this with suitable proportioning of the parts. In addition, the described structure of the present invention is suitable for outdoor use, and because of the rigid inter bracing of the interrupting assemblies 1 by the isolating structures 5, the entire circuit interrupter is suitable for locations, where there may be earthquake shocks, or

other disturbances. The maintenance of a slight pressureand close in a high-pressure region 28, constantly main tained at high-pressure, the separating distance between the isolating contacts 26, 27 need be very small because of the high dielectric strength of the high-pressure gas.

' Because of the particular construction of the operating mechanism, the trip magnet and the closing magnet need bemerely momentarily energized, and the pressure of the gas within the region 92 of the casing 91 will maintain the valves 86, 93 in their moved positions.

The current transformer 35 is located in the lower end of the interrupting housing, which forms the mechanical I support for the breaker, and in addition, encloses the transformer insulating fluid. The space between the porcelain 32 and the insulating tube 36 may house the capacitor elements for the potential device. In addition, this transformer mounting space '34 accomodates the air lines and the operating rods which connect the interrupter to ground potential. By having the blast valve 65 at high potential, with the auxiliary reservoir 6 also at high potential, there is no loss of time between the actuation of the blast valve 65 and the flow of compressed gas about the main and impedance contacts 8, 9, and 11, 12. Thus, the opening operation of the entire breaker is speeded up.

It should be noted that the isolating switch structure may be separated so that one is mounted on each half of the interrupter. Or they may be made entirely as separate pieces of apparatus except that they are operated from the same air supply and their control is coordinated with that of the main breaker.

Although there has been shown and described a specific structure, it is to be clearly understood that the same was merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the invention.

We claim as our invention:

1. A circuit interrupter including an upstanding, cylindrical insulating support casing, an interiorly disposed cylindrical insulating tube, interrupting means supported at the upper end of said upstanding, cylindrical insulating support casing, a potential device for measuring the potential between said interrupting means and ground potential including a plurality of separate series capacitor elements disposed in the annular space between said cylindrical tube and said outer insulating casing, and means tapping oil the voltage across the bottom capacitor element for voltage measurement.

2. The combination in a compressed-gas circuit interruptor of an upstanding, cylindrical weatherproof insulating casing, an interiorly disposed insulating tube, and means including a reducing valve for storing gas without loss in the annular space between said weatherproof casing and said interiorly disposed tube at slightly elevated gas pressure above atmospheric pressure to prevent moisture-laden air from leaking into the circuit interrupter.

3. A compressed-gas circuit interrupter including an upstanding insulator column, a high-pressure reservoir situated on top of said insulator column, a pair of separable contacts associated with said reservoir and separable to establish an arc, gas-blast means including a blast valve controlling exhaust of gas from said reservoir for extinguishing said are, first valve means for dumping high-pressure gas from in back of said blast valve to eiiect the opening thereof, a pair of separable isolating contacts separable in a high-pressure atmosphere which is independent of said high-pressure reservoir, means connecting said pair of isolating contacts electrically in series with said first-mentioned pair of separable contacts,

means exhausting the space in back of one isolating contact to efiect the opening movement thereof including an isolating chamber, second valve means for controlling the pressure within said isolating chamber, operating means including a pivotally mounted valve lever disposed adjacent said high-pressure reservoir for actuating said first and second valve means, and an insulating operating rod extending downwardly through said insulator column from adjacent one end of said pivotally mounted valve lever for effecting operative rotation of said valve lever.

4. A compressed gas circuit interrupter including an upstanding insulator column, a high-pressure reservoir situated on top of said insulator column, a pair of separable contacts associated with said reservoir and separable to establish an arc, gas-blast means including a blast valve controlling exhaust of gas from said reservoir for extinguishing said are, first valve means for dumping high-pressure gas from in back of said blast valve to effect the opening thereof, a pair of separable isolating contacts separable in a high-pressure atmosphere which is independent of said high-pressure reservoir, means connecting said pair of isolating contacts electrically in series with said first-mentioned pair of separable contacts, means exhausting the space in back of one isolating contact to efiect the opening movement thereof including an isolating chamber, second valve means for control-ling the pressure within said isolating chamber, operating means including a pivotally mounted valve lever disposed adjacent said high-pressure reservoir for actuating said first and second valve means, said valve lever making an abutting engagement with said first valve means, and an insulating operating rod extending downwardly through said insulator column from adjacent one end of said pivotally mounted valve lever for elfecting operative rotation of said valve lever.

5. A compressed gas circuit interrupter including an upstanding insulated column, a high-pressure reservoir situated on top of said insulator column, a pair of separable contacts associated with said reservoir and separable to establish an arc, gas blast means including a blast valve controlling exhaust of gas from said serervoir for extinguishing said arc, first valve means for dumping high-pressure gas from in back of said blast valve to effect the opening thereof, a pair of separable isolating contacts separable in a high-pressure atmosphere which is independent of said high-pressure reservoir, means connecting said pair of isolating contacts electrically in series with said first-mentioned pair of separable contacts, means exhausing thes pace in back of one isolating contact to effect the opening movement thereof including an isolating chamber, second valve means for controlling the pressure within said isolating chamber, operating means including a pivotally mounted valve lever disposed adjacent said high-pressure reservoir for actuating said first and second valve means, said valve lever having a lost-motion connection with said second valve means, and an insulating operating rod extending downwardly through said insulator column from adjacent one end of said pivotally mounted valve lever for effecting operative rotation of said valve lever.

6. A compressed-gas circuit interrupter including an upstanding, hollow insulating support column, interrupting means supported upon said hollow insulating support column, a current transformer disposed interiorly within said hollow insulating column to measure the current flow through the interrupter, capacitance dividing means including separate series capacitor elements also disposed interiorly within said hollow insulating column for potential measuring purposes, and said capacitance dividing means being connected between said interrupting means and ground potential.

7. A gas-blast circuit interrupter including a pair of separable contacts, means for effecting the opening of one of said contacts including a control chamber, a high-pressure chamber communicating with the first said control chamber through a port opening in the wall of the first said control chamber, valve means on the highpressure side of said port opening and adapted to control the passage of gas through said port opening, other valve means disposed interiorly within said control chamber for venting the first said control chamber so that the first said control chamber may be at a high pressure or at a relatively lower pressure, means responsive to the pressure within the first said control chamber to effect the opening and closing movements of said one contact, the first said control chamber when vented serving to maintain said valve means over said port opening by the pressure differential thereacross between said high-pressure chamber and said control chamber, and a rocking valve lever pivotally mounted interiorly of said control chamber interconnecting the two valve means so that when one valve means is open the other valve means is closed.

' 8; A gas-blast circuit interrupter including a pair of separable contacts, means for eifecting the opening of one of said contacts including a control chamber, a highpressure chamber communicating with the first said control chamber through a port opening in the wall of the first said control chamber, valve means on the highpressure side of said portopening and adapted to control the passage of gas through said port opening, other valve means disposed interiorly within said control chamber for venting the first said control chamber so that the first said control chamber may be at a high pressure or at a relatively lower pressure, means responsive to the pressure within the first said control chamber to effect the opening and closing movements of said one contact, the first said control chamber when vented serving to maintain said valve means over said port opening by the pressure diiferential thereacross between said highpressure chamber and said control chamber, a rocking valve lever pivotally mounted interiorly of said control chamber and interconnecting the two valve means so that when one valve means is open the other valve means is closed, and actuating means disposed exteriorly of said control chamber having a lost-motion connection with said interconnecting means for initiating the operation thereof.

9. A circuit interrupter of the compressed-gas type including a pairof spaced, upstanding insulator columns, a pair of auxiliary metallic compressed-gas reservoirs supported at line potential at the upper ends of said insulator columns, line-terminal means associated with each metallic reservoir at line potential, an interrupting structure extending upwardly and supported by each auxiliary compressed-gas reservoir and actuable to establish an are, means including a blast of gas from the adjacent auxiliary compressed-gas reservoir to effect extinction of the are established in each interrupting structure, an isolating contact structure including a high-pressure container for electrically bridging the two spaced interrupting structures at the upper ends thereof, at least one pair of separable isolating contacts disposed within said high-pressure container, an operating cylinder, a piston associated with one of said separable isolating contacts and movable Within said operating cylinder, means for exhausting the high-pressure gas within said operating cylinder to efiect opening isolating movement of said one movable isolating contact, and. means utilizing highpressure gas from one of said auxiliary compressed-gas reservoirs at line potential to effect an increase of pressure within said operating cylinder to bring about a closing movement of said one movable isolating contact.

10. Acircuit interrupter of the compressed-gas type including a pair of spaced, upstanding insulator columns, a pair of auxiliary compressed-gas metallic supporting reservoirs supported at line potential at the upper ends of said insulator columns, line-terminal means associated with each metallic reservoir at line potential, an interrupting structure extending upwardly and supported by each auxiliary compressed-gas reservoir and actuable to establish an arc, means including a blast of gas from the adjacent auxiliary compressed-gas reservoir to eiiect ex tinction of the are established in each interrupting structure, an isolating contact structure including a high-pressure container for electrically bridging the two spaced interrupting structures, said isolating contact structure in addition effecting a mechanical interbracing of the upper ends of the two interrupting structures so that a strong and rigid compressed-gas circuit interrupter results, at least one pair of separable isolating contacts disposed within said high-pressure container, an operating cylinder, a piston associated with one of said separable isolating contacts and movable within said operating cylinder, means including a control chamber associated with" said auxiliary compressed-gas reservoir for ex hausting the high-pressure gas within said operatingcyh inder to effect opening isolating movement of said one movable isolating contact, valve means for alternately pressun'zing and exhausting said control chamber, con duit means interconnecting said operating cylinder and said control chamber, and means utilizing high-pressure gas from said control chamber to effect an increase of pressure within said operating cylinder to bring about a closing movement of said one movable isolating contact.

11. The combination in a compressed-gas circuit interrupter of a pair of spaced, upstanding insulator columns, a tank of high-pressure gas at ground potential, a pair of metallic auxiliary compressed-gas reservoirs supported at the upper ends of said two spaced columns at line potential, line-terminal means associated with each metallic reservoir at line potential, conduit means for feeding high-pressure gas from said grounded tank to each of said auxiliary compressed-gas reservoirs, an interrupting structure extending upwardly and supported by each of said auxiliary metallic compressed-gas reservoirs and operable to establish an arc, means including a blast of gas from the adjacently disposed auxiliary compressed-gas reservoir to eiiect extinction of the are established in each interrupting structure, an isolating contact structure including a constantly pressurized container for electrically and mechanically interconnecting the upper ends of the two interrupting structures, a highpressure pipe extending upwardly through one of said interrupting structures and interconnecting said pressun,

ouit interrupting structure of generally inverted U-shape' supported upwardly of said elongated grounded highpressure storage tank, said generally inverted 'U-shaped interrupting structure including a pair of spacedupstanding insulator columns having metallic auxiliary compressed-gas reservoirs disposed at their upper ends at line potential, line-terminal means associated with each metallic reservoir at line potential, arc-establishing and extinguishing means surmounting each of said auxiliary compressed-gas reservoirs and extending upwardly therefrom, an elongated isolating contact structure including an elongated high-pressure container for electrically and mechanically interconnecting and interbracing the upper ends of said surmounting arc-establishing and extinguishing means, at least one pairof separable isolating contacts separable within the high-pressure container, and at least one of said spaced upstanding insulator columns constituting a current-transformer compartment within which is positioned a current transformer for the circuit interrupter.

13. The combination in a compressed-gas circuit interrupter of anupstanding insulator column, a blast valve and separable contact means associated with the upper end of said insulator column, dump-valve means for opening said blast valve, a reservoir tank containing gas at high pressure, said blast valve controlling a blast of gas issuing from said reservoir tank to effect extinction upper end of said upstanding insulator column for actuating said first and second valve means, operative to tation of said pivotally mounted valve lever effecting sequential actuation of said first and second valve means, and an insulating operating rod extending downwardly through said insulator column from adjacent one end of said pivotally mounted valve lever for eifecting operative rotation of said valve lever.

14. A compressed-gas circuit interrupter including an upstanding insulator column, a high-pressure auxiliary reservoir supported by said insulator column, separable main contacts associated with said high-pressure auxiliary reservoir, a blast-valve controlling a blast of gas from said reservoir to said separable main contacts, a serially related separable pair of isolating contacts electrically connected in series with said main contacts, a control chamber disposed adjacent said high-pressure auxiliary reservoir and have a port connection therewith, a vent port for said control chamber for venting the same at certain times, first valve means for controlling said blast valve, interlocking second valve means for either closing said port connection and opening said vent port or opening said port connection and closing said vent port, means responsive to the pressure within said control chamber to effect opening of one of said isolating contacts, and operating means disposed adjacent said high-pressure auxiliary reservoir for sequentially operating said first and second valve means.

15. A compressed-gas circuit interrupter including an upstanding insulator column, a high-pressure auxiliary reservoir supported by said insulator column, separable main contacts associated with said high-pressure auxiliary reservoir, a blast valve controlling a blast of gas from said reservoir to said separable main contacts, a serially related separable pair of isolating contacts electrically connected in series with said main contacts, a control chamber disposed adjacent said high-pressure auxiliary reservoir and have a port connection therewith, a vent port for said control chamber for venting the same at certain times, first valve means for controlling said blast valve, interlocking second valve means for either closing said port connection and opening said vent port or opening said port connection and closing said vent port, means responsive to the pressure within said control chamber to efiect opening of one of said isolating contacts, a pivotally mounted valve lever for sequentially actuating said first and second valve means disposed adjacent said high-pressure auxiliary reservoir, and an insulating rod connected to said valve lever and extending down through said insulator column to ground potential.

16. A circuit interrupter of the compressed-gas type including a pair of laterally-spaced upstanding insulator columns, a pair of metallic supporting compressed-gas reservoirs positioned at line potential at the upper ends of said insulator columns, line-terminal means associated with each metallic reservoir for connecting the circuit interrupter into the controlled circuit, a pair of laterallyspaced upstanding interrupting structures extending upwardly and supported by the respective compressed-gas reservoirs, separable gas-blast-actuated contacts associated with each interrupting structure for establishing an arc therein, blast-valve means associated with each compressed-gas reservoir for forcing a blast of compressed gas from the respective compressed-gas reservoir toward the established arc to effect the extinction thereof, an elongated pressurized isolating chamber electrically and mechanically bridging the upper ends of the two laterallyspaced interrupting structures, at least one pair of separable isolating contacts disposed within said elongated pressurized isolating chamber, means electrically connecting the isolating contacts in series with said separable gas-blast-actuated contacts, a pressure connection extending upwardly through one interrupting structure interiorly thereof and pneumatically interconnecting the pressurized isolating chamber with one of said metallic supporting compressed-gas reservoirs, and means for sequentially opening first the two pairs of separable gas- 14 blast-actuated contacts and secondly the serially related separable isolating contacts to effect an isolating gap in the pressurized isolating chamber.

17. A circuit interrupter of the compressed-gas type including a pair of laterally-spaced upstanding insulator columns, a pair of metallic supporting compressed-gas reservoirs positioned at line potential at the upper ends of said insulator columns, line-terminal means associated with each metallic reservoir for connecting the circuit interrupter into the controlled circuit, a pair of laterallyspaced upstanding interrupting structures extending upwardly and supported by the respective compressed-gas reservoirs, separable gas-blast-actuated contacts associated with each interrupting structure for establishing an arc therein, blast-valve means associated with each com pressed-gas reservoir for forcing a blast of compressed gas from the respective compressed-gas reservoir toward the established arc to effect the extinction thereof, an elongated pressurized isolating chamber electrically and mechanically bridging the upper ends of the two lateraL ly-spaced interrupting structures, at least one pair of separable isolating contacts disposed within said elongated pressurized isolating chamber, means electrically connecting the isolating contacts in series with said separable gas-blast-actuated contacts, pneumatic means for operating said separable isolating contacts including a control chamber positioned interiorly of one of said compressed-gas reservoirs, first valve means for eflecting opening of one of said blast-valve means, second valve means for alternately pressurizing and exhausting said control chamber, and means for sequentially operating first said first valve means and subsequently said second valve means.

18. A compressed-gas circuit interrupter including a pair of separable contacts separable to establish an arc, a high-pressure chamber, a blast valve for forcing a blast of high-pressure gas out of said chamber toward said are to effect the extinction thereof, a dump valve for dumping the gas in back of said blast valve and having an abutment extension, a pair of serially related isolating contacts, pneumatic means for operating said series pair of isolating contacts subsequent to are extinction including a control chamber positioned interiorly of said highpressure chamber, second valve means for alternately pressurizing and exhausting said control chamber and also having an abutment extension, a pivotally mounted valve lever, and said pivotally mounted valve lever making sequential abutment engagement with said two abutment extensions, whereby first the blast valve opens and subsequently the second valve means pressurizes the control chamber to efiect isolating contact opening movement.

19. A circuit interrupter of the compressed-gas type including a pair of laterally-spaced upstanding insulator columns, a pair of metallic supporting compressed-gas reservoirs positioned at line potential at the upper ends of said insulator columns, line-terminal means associated with each metallic reservoir for connecting the circuit interrupter into the controlled circuit, a pair of laterallyspaced upstanding interrupting structures extending upwardly and supported by the respective compressed-gas reservoirs, separable gas-blast-actuated contacts associated with each interrupting structure for establishing an arc therein, blast-valve means associated with each compressed-gas reservoir for forcing a blast of compressed gas from the respective compressed-gas reservoir toward the established arc to eifect the extinction thereof, an elongated pressurized isolating chamber electrically and mechanically bridging the upper ends of the two laterally-spaced interrupting structures, at least one pair of separable isolating contacts disposed within said elongated pressurized isolating chamber, means electrically connecting the isolating contacts in series with said separable gas-blast-actuated contacts, a pressure connection extending upwardly through one interrupting strucmeans ture interiorly thereof and pneumatically interconnecting the pressurized isolating chamber with one ofsaid metallic supporting compressed-gas reservoirs, and means in cluding a pivotally-mounted valve lever positioned adjacent one of said metallic reservoirs for sequentially opening first the two pairs of separable gas-blast-actuated contacts and secondly the serially related separable isolating contacts to efiiect an isolating gap in the pressurized isolating chamber.

20. A circuit interrupter of the compressed-gas type including a pair of laterally-spaced upstanding insulator columns, a pair of metallic supporting compressed-gas reservoirs positioned at line potential at the upper ends of said insulator columns, line-terminal means associated with each metallic reservoir for connecting the circuit interrupter into the controlled circuit, a pair of laterallyspaced upstanding interrupting structures extending upwardly and supported by the respective compressed-gas reservoirs, separable gas-'blast-actuated contacts associated with each interrupting structure for establishing an arc therein, blast-valve means associated with each compressed-gas reservoir for forcing a blast of compressed gas from the respective compressed-gas reservoir toward the established arc to efiect the extinction thereof, an elongated pressurized isolating chamber electrically and mechanically bridging the upperends of the two laterally-spaced interrupting structures, at least one pair of separable isolating contacts disposed within said elongated pressurized isolating chamber, means electrically connecting the isolating contacts in series with said separable gas-blast-actuated contacts, a pressure connection extending upwardly through one interrupting structure interiorly thereof and pneumatically interconnecting the pressurized isolating chamber with one of said metallic supporting compressed-gas reservoirs, means including a pivotally-mounted valve lever positioned ad jacent one of said metallic reservoirs for sequentially opening first the two pairs of separable gas-blast-actuated contacts and secondly the serially related separable isolating contacts to efiect an isolating gap in the pressurized isolating chamber, and an insulating operating rod ex tending upwardly interiorly of one of said insulator columns and pivotally connected to said valve lever.

21. A circuit interrupter of the compressed-gas type including a pair of laterally-spaced upstanding insulator columns, a pair of metallic supporting compressed-gas reservoirs positioned at line potential at the upper ends of said insulator columns, line-terminal means associated with each metallic reservoir for connecting the circuit in-' terrupter into the controlled circuit, a pair of laterallyspaced upstanding interrupting structures extending upwardly and supported by the respective compressed-gas reservoirs, separable gas blast-actuated contacts associated with each interrupting structure for establishing an arc therein, blast-valve means associated with each compressed-gas reservoir for forcing a blast of compressed gas from the respective compressed-gas reservoir toward the, established arc to eifect the extinction thereof, an elongated pressurized isolating chamber electrically and mechanically bridging the upper ends of the two laterally-spaced interrupting structures, at least one pair of separable isolating contacts disposed Within said elongated pressurized isolating chamber, means electrically connecting the isolating contacts in series with said separable gas-blast-actuated contacts, pneumatic means for operating said separable isolating contacts including a control chamber positioned interiorly of one of said compressed-gas reservoirs, first valve means for effecting opening of one of said blast-valve means, second valve means for alternately pressurizing and exhausting said control chamber, and means including a pivotallymounted valve lever positioned adjacent one of said metallic reservoirs for sequentially operating first said first valve means and subsequently said second valve means.

22. A circuit interrupter of the compressed-gas type including acpair of laterally-spaced upstanding insulator columns, a pair of metallic supporting compressed-gas reservoirs positioned at line potential at the upperends of said insulator columns, line-terminal means associated with each metallic reservoir for connecting the circuit interrupter into the controlled circuit, a pair of laterallyspaced upstanding interrupting structures extending upwardly and supported by the respective compressed-gas reservoirs, separable gas-blast-actuated contacts associated with each interrupting structure for establishing an arc therein, blast-valve means associated with each compressed-gas reservoir for forcing a blast of compressed gas from the respective compressed-gas reservoir toward the established arc to effect the extinction thereof, an elongated pressurized isolating chamber electrically and mechanically bridging the upper ends of the two laterally-spaced interrupting structures, at least one pair of separable isolating contacts disposed within said elongated pressurized isolating chamber, means electrically connecting the isolating contacts in series with said separable gas-blast-actuated contacts, pneumatic means for operating said separable isolating contacts including a control chamber positioned interiorly of one of said compressed-gas reservoirs, first valve means for elfecting opening of one of said blast-valve means, second valve means for alternately pressurizing and exhausting said control chamber, means including a pivotally-mounted valve lever positioned adjacent one of said metallic reservoirs for sequentially operating first said first valve means and subsequently said second valve means, and an insulating operating rod extending upwardly interiorly of one of said insulator columns and pivotally connected to 7 said valve lever.

23. A circuit interrupter of the compressed-gas type including a pair of laterally-spaced upstanding insulator columns, a pair of metallic supporting compressed-gas reservoirs positioned at line potential at the upper ends of said insulator columns, line-terminal means associated with each metallic reservoir for connecting the circuit interrupter into the controlled circuit, a pair of laterallyspaced upstanding interrupting structures extending upwardly and supported by the respective compressed-gas reservoirs, separable gas-blast-actuated contacts associated with each interrupting structure for establishing an arc therein, blast-valve means associated with each compressed-gas reservoir for forcing a blast of compressed gas from the respective compressed-gas reservoir toward the established arc to effect the extinction thereof, an

elongated pressurized isolating chamber electrically and mechanically bridging the upper ends of the two laterallyspaced interrupting structures, at least one pair of separable isolating contacts disposed within said elongated pressurized isolating chamber, means electrically connect-' ing the isolating contacts in series with said separable gas-blast-actuated contacts, pneumatic means for operating said separable isolating contacts including a control chamber positioned interiorly of one of said compressedgas reservoirs, first valve means for efiecting opening of one of said blast-valve means, second valve means including a pivotally mounted interlocking rocking valve lever positioned internally of said control chamber for alternately pressurizing and exhausting said control chamber, and means for sequentially operating first said first valve means and subsequently said second valve means. 7

24. A circuit interrupter of the compressed-gas type including a pair of laterally-spaced upstanding insulator columns, a pair of metallic supporting compressed-gas reservoirs positioned at line potential at the upper ends of said insulator columns, line-terminal means associated with each metallic reservoir for connecting the circuit interrupter into the controlled circuit, a pair of laterallyspaced upstanding interrupting structures extending up- 'wardly and supported by the respective compressed-gas reservoirs, separable gas-blast-actnated contacts associated with each interrupting structure for establishing an arc therein, blast-valve means associated with each compressed-gas reservoir for forcing a blast of compressed gas from the respective compressed-gas reservoir toward the established arc to eifect the extinction thereof, an elongated pressurized isolating chamber electrically and mechanically bridging the upper ends of the two laterally-spaced interrupting structures, at least one pair of separable isolating contacts disposed within said elongated pressurized isolating chamber, means electrically connecting the isolating contacts in series with said separable gas-blast-actuated contacts, pneumatic means for operating said separable isolating contacts including a control chamber positioned interiorly of one of said compressedgas reservoirs, first valve means for efiecting opening of one of said blast-valve means, second valve means including a pivotally mounted interlocking rocking valve lever positioned internally of said control chamber for alternately pressurizing and exhausting said control chamber, the rocking valve lever having an extension protruding out of said control chamber which makes abutment with a part of said sequential operating means, and means for sequentially operating first said first valve means and subsequently said second valve means.

25. A compressed-gas circuit interrupter including a pair of separable contacts separable to establish an are, a high-pressure chamber, a blast valve for forcing a blast of high-pressure gas out of said chamber toward said arc to effect the' extinction thereof, a dump valve for dumping the gas in back of said blast valve and having an abutment extension, a pair of serially related isolating contacts, pneumatic means for operating said series pair of isolating contacts subsequent to are extinction including a control chamber positioned interiorly of said high-pressure chamber, second valve means including an interlocking rocking valve lever positioned interiorly of said control chamber and pivotally mounted therein for alternately pressurizing and exhausting said control chamber and also having an abutment extension, a pivotally mounted valve lever, and said pivotally mounted valve lever making sequential abutment engagement with said two abutment extensions, whereby first the blast valve opens and subsequently the second valve means pressurizes the control chamber to effect isolating contact opening movement.

26. A compressed-gas circuit interrupter including a pair of separable contacts separable to establish an arc, a high-pressure chamber, a blast valve for forcing a blast of high-pressure gas out of said chamber toward said are to eifect the extinction thereof, a dump valve for dumping the gas in back of said blast valve and having an abutment extension, spring means being provided to bias said dump valve to the closed position, a pair of serially related isolating contacts, pneumatic means for operating said series pair of isolating contacts subsequent to are extinction including a control chamber positioned interiorly of said high-pressure chamber, second valve means for alternately pressurizing and exhausting said control chamber and also having an abutment extension, a pivotally mounted valve lever, a lost-motion connection being provided be tween the end of the valve lever and the second-mentioned abutment extension, and said pivotally mounted valve lever making sequential abutment engagement with said two abutment extensions, whereby first the blast valve opens and subsequently the second valve means pressurizes the control chamber to eifect isolating contact opening movement.

References Cited in the file of this patent UNITED STATES PATENTS 2,306,186 Rankin Dec. 22, 1942 2,357,138 Seeley Aug. 29, 1944 2,419,446 Flurscheim Apr. 22, 1947 2,447,656 Ludwig et a1. Aug. 24, 1948 2,459,600 Strom Jan. 18, 1949 2,459,612 Baker Jan. 18, 1949 2,481,996 Gruenwald et al Sept. 13, 1949 2,554,974 Beatty May 29, 1951 2,574,334 Latour Nov. 6, 1951 2,643,315 Forwald June 23, 1953 2,708,700, Thommen May 17, 1955 2,747,055 Forwald May 22, 1956 2,766,348 Forwald Oct. 9, 1956 2,786,119 Forwald Mar. 19, 1957 2,828,392 Leopold Mar. 25, 1958 FOREIGN PATENTS 856,014 Germany Nov. 17, 1952 

